A conflict that has been raging in South Sudan since December has been characterised by extraordinary acts of cruelty against civilians, war crimes and possibly crimes against humanity. China may well be enabling these crimes, whether it intends to or not.

Chinese officials have publicly stated their commitment to peace and stability in South Sudan and the region, and have supported the peace talks under way in Addis Ababa.

But the sale of US$38 million worth of missiles, grenade launchers, machine guns and ammunition to the government of South Sudan, reported last month, says otherwise.

The likely use of those weapons by parties to the conflict in South Sudan would contribute to the grave human rights abuses that have characterised the conflict.

The conflict began in the capital, Juba, in December, triggered by a power struggle between President Salva Kiir, who is ethnic Dinka, and former vice-president Riek Machar, from the Nuer ethnicity. The fighting quickly took on an ethnic dimension. Government forces carried out widespread killings, including a gruesome massacre, and detained hundreds of Nuer men in Juba.

These atrocities triggered reprisal killings of ethnic Dinka in the town of Bor and other parts of the country. In the following weeks and months, conflict spread, and with it, horrible abuses of civilians by both sides in Bor, and the towns of Bentiu and Malakal, all of which have changed hands many times.

Throughout, the two sides have completely ignored international humanitarian law, the "laws of war", by killing civilians in their homes and in churches, hospitals and other places they thought they would be safe, often because of their ethnicity or perceived political affiliation. The forces have destroyed huge swathes of towns, including hospitals, churches and schools, and pillaged everything they could find.

The results: thousands killed, property destroyed, and an estimated 1.5 million people fleeing their homes, with around 100,000 now taking refuge in UN compounds in appalling conditions.

Large numbers of people are still hiding in the bush, amid a looming famine because people have not been able to plant crops.

Under these dire circumstances, it is entirely foreseeable that any more weapons flowing into the country could contribute directly to more civilian destruction and the unlawful killing and abuse of civilians.

Human Rights Watch and other groups have called on the United Nations to impose an immediate arms embargo on South Sudan, and to make sure that no more weapons flow into the country. China, as a permanent member of the UN Security Council, should make sure this happens and it should stop supplying weapons to South Sudan.

Unless China breaks with the past practice of rejecting arms embargoes, its claims to want to see an end to abuses in South Sudan are just empty words.